Urban Geology: field trips in the city centre to discover lithological geodiversity

Outdoor activities are a powerful tool in teaching Earth Sciences. However, most secondary schools have great difficulties in organizing field trips to geological sites far from their own location for several reasons (e.g., travel distance and costs, insurances, availability of time). The project “Urban Geology” has been developed in recent years by a multidisciplinary team in the frame of the “Piano Lauree Scientifiche” (i.e., “Scientific Degree Plan”, an initiative of the Ministry of Education aimed to sustain Science, Technology and Mathematics studies). The project offers to Earth Science teachers at high schools a low-cost opportunity for outdoor geological activities. A standard itinerary is proposed in the city centre of Milan (from San Babila to Duomo along Corso Vittorio Emanuele) and it is supported by a short guide made available to the school teachers, allowing them to lead the excursion by themselves. Along the itinerary it is possible to observe a variety of rocks of different origins, used as building material: sedimentary (i.e., conglomerates, sandstones, limestones), magmatic (i.e., granites s.l., rhyolites, trachytes), metamorphic (i.e., marbles, orthogneisses). Through additional information reported in the guide on the provenance area and historical use of each lithotype through times, the teacher may extend the discussion to other topics, as, for example, environmental problems related to use of rocks and minerals as georesources, or commercial routes in the different historical periods, or architecture and art transformation through times. The project has recently been implemented leaning on the GeoODK Collect App for Smartphone. In this framework a specific form for collecting data was set and shared with students to be applied both around Milan or in their own cities or towns. They can take pictures of rocks used for buildings or monuments or other urban occurrences, they can geolocalize the site, describe and classify the rock and add information on its provenance or other details and upload all the materials, making them available to other users. The final aim is to provide the material to students to create their own itineraries to be shared through the devoted website (https://ona.io/). One of the most significant experimentation of the methodology is in progress within the framework of the “School – Job Alternance” project in collaboration with several schools in the Lombardy area.